A search has resumed for a man who disappeared while swimming at a beach north of Perth.

The 30 year-old man was last seen by family and friends swimming out to a reef marker at Yanchep Lagoon around 6:00 pm on Saturday night.

It is believed he got caught in a rip.

A search that night and yesterday failed to find him.

A search involving water police, divers and aircraft resumed at first light this morning.